Influence of a jet vortex generator on a turbulent boundary layer 2: Analysis of unsteady characteristics

We analyze unsteady characteristics of the flow resulting from the interaction between a longitudinal vortex-generated by jet injection from a wall-and a turbulent boundary layer. Velocity fields are measured using particle image velocimetry. Our data analysis includes the assessment of turbulence anisotropy and characteristic length scales of turbulent structures, as well as proper orthogonal decomposition. The results reveal mutual interaction between the turbulent boundary layer and the longitudinal vortex, which depends on the vortex intensity. It is demonstrated that the jet vortex generator significantly alters not only the mean flow but also the unsteady characteristics of the turbulent boundary layer.